Optically active fluoroalkyl ethylene oxides are important compounds as various medicinal and agricultural chemical intermediates. As methods for producing optically active 2-trifluoromethyl ethylene oxide, Non-patent Publication 1 discloses a method by an asymmetrical oxidation of 1,1,1-trifluoropropene using microorganism, Non-patent Publication 2 discloses a method by a kinetic optical resolution of racemic 2-trifluoromethyl ethylene oxide, Non-patent Publication 3 discloses a method in which 3-bromo-1,1,1-trifluoro-2-propanone is asymmetrically reduced by an asymmetric reducing agent, and the obtained optically active 1-bromo-3,3,3-trifluoroisopropyl alcohol is treated with base to achieve a ring closure, Non-patent Publication 4 discloses a method in which optically active 3,3,3-trifluorolactic acid is obtained by using an optical resolution agent, and a sulfonic acid ester obtained by conducting a multistep procedure, such as protecting the substituent with a protecting group, deprotecting, esterification, etc., is treated with base, and Patent Publication 1 discloses a method in which optically active 3,3,3-trifluoro-1,2-propanediol is increased by recrystallization in optical purity, followed by conversion into optically active 1-chloro-3,3,3-trifluoroisopropyl alcohol and then treatment with base to achieve a ring closure.
Meanwhile, the present inventors disclose in Patent Publication 2 a method in which optically active 3,3,3-trifluorolactic acid is converted into optically active 3,3,3-trifluoro-1,2-propanediol, followed by conversion into a halohydrin through a cyclic sulfuric acid ester and then into optically active 2-trifluoromethyl ethylene oxide.
Furthermore, as to optically active 2-monofluoromethyl ethylene oxide, Non-patent Publication 2 discloses a method by a kinetic optical resolution of racemic 2-monofluoromethyl ethylene oxide.
On the other hand, no synthesis example of optically active 2-difluoromethyl ethylene oxide has been known so far.